Positive drive assembly for constant tension, film handling machine



Dec. 23, 1958 w. ENKELMANN POSITIVE DRIVE ASSEMBLY FOR CONSTANT TENSION, FILM HANDLING MACHINE 2 Sheets-Sheet 1 Filed Aug. 9, 1956 INVENTOR. W4; rz/e EVA 4 MAN/V 33% TTOZAL).

Dec. 23, 1958 w. ENKELMANN' 30 POSITIVE DRIVE ASSEMBLY FOR CONSTANT TENSION, FILM HANDLING MACHINE Filed Aug. 9, 1956 2 Sheets-Sheet 2 Jay 6668 1 55 T I I i INVENTOR. l l/xu me [Am 4 MAM/A United States Patent POSITIVE DRIVE ASSEMBLY FOR CONSTANT TENSION, FILM HANDLING MACHINE Walter Enkelrnann, Los Angeles, Calili, nssignor to Unicorn Engineering Corporation, Los Angeles, Calif., a corporation of California Application August 9, 1956, Serial N0. 603,101

16 Claims. (Cl. 271-2.s)

This invention relates to apparatus for handling motion picture film and particularly to a positive drive as sembly for use on a film developing machine of the character disclosed in my copending application Serial No. 560,413, entitled Friction Drive, filed January 20, 1956 and in Patent No. 2,126,170 issued February 7, 1939.

In developing motion picture film, it is the usual practice to run a continuous length of film through a series of solution tanks and one or more drying cabinets. Generally the film is threaded about a series of film rollers at the tops and bottoms of the tanks and drying cabinets so there is formed in each of the tanks and cabinets a plurality of film loops. In the machine disclosed in the above mentioned copending application and patent, the film is advanced through the tanks and cabinets by means of friction driving rollers engaged with certain of the film rollers.

In order to compensate for stretching and shrinking of the film as it becomes wet during passage through the processing solutions and becomes dry during passage through the drying cabinets, so as to maintain a substantially constant tension in the film, the film rollers engaging the friction drive rollers in this machine are resiliently mounted to permit disengagement of these rollers in response to an increase in tension in the film and re-engagement of the rollers upon lessening of the tension. A substantially constant tension is thereby maintained in the film. The apparatus is so adjusted that the film tension will be sufiicient to assure proper frictional driving of the film from the film rollers and yet not so excessive as to result in mechanical stretching of the film which distorts the images and sound track thereon.

To assure proper developing of the film, the latter must be retained in the developing solution a precise period of time which is dependent on the type of solution and the temperature of the solution. It will be evident, therefore, that for a given developing solution at a given temperature, the physical size of the developing machine and the rate of film movement necessary to assure a proper developing time for the film are, in a sense, inter-related and dependent one on the other. That is, the greater the physical size of each developing tank in the apparatus and/or the number of such developing tanks the greater will be the number of film loops which may be contained in each tank and the total number of film loops which may be contained in the several tanks, and therefore, the greater will be the transit time of a given portion of the film through the developing solution. Accordingly,'the larger the physical size of the developing tanks and/or the number of tanks, and therefore the larger the physical size of the developing machine, the more rapid may be the rate at which the film is moved through the machine. Conversely, the smaller the size of the developing machine, as a result of de creased size of the developing tanks and/or the number of such tanks, the slower must be the rate of film movement through the machine toassure the necessary time of movement of the film through the developing solution.

In most film developing laboratories, space is at a premium so that the size of the developing machine must be kept at a'minimum whereas the trend in film processing is toward extremely high speed film developing operations. In order to accomplish proper developing of the film when it is fed at a high rate of speed through a relatively short or small developing machine, resort is had to hot developing solutions, that is, solutions which are heated to an elevated temperature in order to speed up the chemical reactions which occur during the developing process. Owing to the accelerated rate of these chemical reactions, the period of time which a given portion of the film is retained in the developing solution becomes extremely critical, and even a slight variation in this time results in improper developing of the film.

In the developing machines of the above mentioned copending application and patent, as previously mentioned, the film is fed through the machine by the friction drive rollers engaging the film rollers, the film being drawn onto the first film roller of the developing machine from a supply reel through various guide rollers. Often the tension in the run of film leading from the supply reel to the developing machine varies slightly due, perhaps, to slight binding in the guide rollers over which this run of film is passed or slight variations in the friction of the supply reel and/or the progressively decreasing diameter of the roll of film on the supply reel as the film is unwound therefrom. These variations in tension in the incoming run of film are, of course, reflected in corresponding variations in tension in the film loops within the developing machine. As indicated above, the friction drive rollers are automatically disengaged from the film rollers to momentarily discontinue feeding of the film if the tension in the film loops increases above a predetermined value. This momentary cessation of driving of the film results in portions of the film remaining in the developing solution for slightlyv prolonged periods of time. This generally results in improper developing of such portions of the film where the machine is a high speed,-short developing machine employing hot developing solutions.

A general object of this invention is the provision of a positive drive assembly for use on developing machines of the character described for positively driving a film roller in the first tank of the developing machine to obtain a constant rate of feed of film into the machine and thereby obtain a more constant rate of movement of the film through the machine.

Another object of the invention is the provision of a positive drive assembly for use on developing machines of the character described for accomplishing accurately controlled rate of film movement through the machine and, therefore, accurately controlled time of immersion of the film in the developing solutions in the machine.

Yet another object of the invention is the provision of a positive drive assembly for use on developing machines oftheclass described'which is in the nature of an attachment capable of i being quicklyandeasily installed on such machines.

A further object of the invention is the provision of a positive drive assembly for film developing machines of the class described which does not impede disengage ment of the friction drive rollers from the film rollers to maintain substantially constant tension in the loops of film within the machine.

A still further object of the invention is the provision of a'positive' drive assembly for film developing machines of the class described which is relatively simple in construction, inexpensive to manufacture, and'ot'herwise well suited to its intendedpurpose.

Other objects, advantages, and features of the invention will--become readily apparent as the description proceeds.

The illustrative embodiment of the invention consists brieflyof a' relatively thin,- generally rectangular gear case in which are journaled' a pair of meshing gears having hollow hubs opening through opposite sides of the gear case. One of these hubs is adapted to receive the drive shaft of the first bank of the film developing machine while the hub of the other gear is adapted to receive the shaft on which the film rollers in the first bank of the machine are mounted. The hub of this latter gear extends beyond opposite sides of the gear case and has rigidly fixed on one ofits ends one of the film rollers in the first bank. Another of the film rollers in the first bank is rotatably mounted on the'other end of this hub.

This latter hub mounts arr-internal bushing through which the film roller shaft extends and which forms an axially convex bearing surface engageable with the shaft to accommodate'rocking of the latter relative to the gear. In assembly of the drive on a developing machine, one of the friction rollers in the first bank of the machine is replaced by the present drive. The drive shaft which extends through the first mentioned gear of the drive assembly mounts a friction roller engageable with film rollers on the shaft which extends through the other gear of the assembly. The above mentioned bushing accommodates tilting of the film roller shaft relative to the assembly to permit disengagement of this friction roller and itsrespective film rollers during operation of the machine in response to an'increase in tension in the corresponding film loops.

A better understanding of the invention may be had from the following detailed description taken in connection with the accompanying drawings, wherein:

Fig. 1 is a section taken transversely through a developing machine of the type disclosed in my aforementioned copendingapplication and showing the positioning of the present positive drive assembly therein;

Fig. 2 is an enlarged section taken along line 2-2 of Fig. 1;

Fig. 3 is an enlarged section taken along line 33 of Fig. 2;

Fig. 4 is an enlarged section taken along line 4-4 of Fig. 3; and

Fig. 5 is an enlarged section taken along line 5--5 of Fig. 4.

The developing machine of my copending application comprises a series of banks arranged in end toend fashion and each including a tank for containing film processing solutions and subsequent drying cabinets.- The first one of these tanks is shown at- 19 in Fig. 1 of the attached drawings. Associated with tank is a film'guiding' and supporting structure 12 including upper and lower film rollers 14 and 16 which are carried on a hoist frame 18 which may be elevated to raise the several film rollers 14 and 16 out of tank 10.

As more fully discussed inmy above mentioned copending application and in the' above mentionedpatent, film 20'," to be processed, leads from'a supply reel, not

shown, into the first tank 10 of the developing machine and is wound about the several upper and lower rollers 14 and 16 in the manner indicated. From the upper right hand roller of the first bank, the film leads to the upper right hand roller of the second bank (not shown) and is then looped around the several film rollers in the second bank and thence to. the third bank (not shown) in the machine and so on. As just indicated solution tank 10 and film rollers 14 and 16 shown in the drawing comprise the first of such banks of the developing machine, the remainder of the latter being omitted since it forms no part of this invention.

As more fully discussed in" my copending application, the elevating hoist 18 comprises briefly leftand right hand drive frames 22 and 24, respectively, in the inner walls of which is journaled a drive shaft 26 which is rotated in the direction indicated by drive mechanism 23 contained within the left hand drive frame 22.

Each of the drive frames includes a horizontal flange 30 in which are fixed a pair of depending hanger supports 32. A pair of bearing blocks 34 are fixed to the lower ends of the hanger supports 32 and journaled therein are opposite ends of an idler roller shaft 36 on which are journaled the lower film rollers 16. The upper film rollers 14 are journaled on an upper shaft 38 having its opposite ends supported for rotation in a pair of bearing blocks 43' which are movable axially on the hanger rods' 32. These latter bearing blocks 40 are resiliently sup ported on a pair of compression springs 42 encirclingthe hanger rods 32 and bearing at the lower ends againsfi adjustable sleeves 44. Sleeves 44 may be adjusted axially of the hanger rods 32 by manipulation of upper knurled are frictionally driven by the drive roller.

Figs. 2-4. As discussed in my above mentioned copending application, this produces a resultant force on the hanger rods which is directed-axially ofthe latter, during operation of the machine, so that oscillation of 'the supports is eliminated. It will become apparent, however,

as the description proceeds that the positive drivc assembly of this invention may also be employed with a film developing machine of the type disclosed in the above mentioned patent wherein the drive shaft and film roller shafts 36 and 38-are not so ofi'set.

Since the film developing machine is fully and clearly described in my above mentioned copending application, no further description of its construction will be given here. Suifice it to say that during normal operation of the machine, the upper film rollers 14 engage the friction drive roller 48 so as to be driven from the latter and the film 20 is frictionally driven by the film'rollers so that the film is moved through the machine. The drive rollers in succeeding banks of the developing machine may be of gradually increasing size, as discussed in the above mentioned patent, if desired, 50' that the slack in the film is continuously taken up. In the event the tension in the loops of film increases above a predetermined value, determined by the adjustment of the sleeves 44 on the hanger rods 32, the film rollers 14, driven from the drive roller 48,- will, together with the right hand end of the upper shaft 38, be moved away from the drive roller,-against the action of the springs 42, to discontinue driving of the drive rollers until the tension in the film decreases to its normal value.

In my prior film developing machine of this-character, a pair of friction drive rollers are mounted on the upper shaft 33 and'the film 20 is drawn from the supply reel, not shown, to thedeveloping machine by virtue of the above cliscus'se 'd frictional driving of the film rollers by the driverolle'rs and the film' by the film rollers. This invention proposes the replacement of the left hand one of these drive rollers, in the prior developing machine, with a positive drive assembly 50-which acts to positively drive the second film roller, designated as 14a.

During operation of the machine, therefore, roller 14a is continuously, positively driven regardless of the tension in the film loops within'the first bank and the film is fed into the first bank from the supply reel (not shown) at a constant rate. In effect, therefore, the incoming run 20a of film leading from thev supply reel .(not shown) to the bank is isolated from the film'developing machine so that variations in the tension in such incoming run will not effect the tension in the film loops in the developing machine. Accordingly, as more fully discussed below, a more constant rate of film movement through the developing machine is achieved and the time of immersion of the film in the developing solution is accurately controlled as is necessary in high speed, short length developing machines utilizing hot developing solutions.

Referring now to Figs. 2-5, the drive assembly 50 comprises a gear case 52 including upper and lower sections 54 and 56 provided with abutting flanges 60 and 62 joined by bolts 64.

The upper section 54 includes a pair of spaced walls 66 and 68 the spacing between which is maintained by a pair of spacers 70 (Fig. 5) at the upper corners of the walls and which are secured together by bolts 72 passing through alined holes in the walls and spacers. These two walls 66 and 68 are centrally formed with outwardly projecting, centrally bored hubs 74 and 76 in which are tightly fitted bushings 78 and 80. i

The lower section 56 is generally similar to the upper section 54 and includes a pair of spaced, parallel walls 82 and 84 the spacing between which is maintained by spacers and which are secured together by bolts 88 passing through alined bores in the walls 82 and 84 and the spacers. The walls 82 and 84 are also formed with outwardly projecting, centrally bored hubs 90 and 92 which are of somewhat lesser axial extent than the hubs 74 and 76 on the upper section 54 and have frictionally fitted therein bushings 94 and 96.

Rotatably positioned between the walls of the upper and lowersections 54 and 56.21re a pair of meshing gears 98 and 100 having the same number of teeth so as to provide a one-to-one drive. The upper gear 98 has a central, axially bored hub 162 which is journaled in the bushings 78 and 86 of the upper section 54 and which, in the assembled condition of the drive assembly 54 on the developing machine, receives the drive shaft 26. A set screw 104 threaded in the gear'hub 102 locks the gear98 to the shaft 26 for driving of the former by the latter.

The lower gear 100 includes a hub 106 which is journaled in the lower bushings 94 and 96 and has slightly externally reduced end portions which extend beyond opposite ends of the hubs 90 and 92 of the lower section 52. The positively driven film roller 14a is mounted on the left hand end of the hub 106 and is keyed thereto, as shown, so as to be positively driven from the gear 100. The other end of the gear hub 106 has a third film roller 14!) rotatably mounted thereon and retained in position by means of a bearing 108 backed up by a snap ring 110.

Hub 106 of the lower gear 100 has a bore 112 extending into its right hand end which is reduced to form a seat for a bushing 114. Bore 112 is then continued in a still further slightly reduced bore opening through the left hand end of the hub. The smallest diameter portion of the bore 112 through the hub 196 is somewhat larger than the upper roller shaft 38 so that the latter may be loosely received therein. Bushing 114 has its inner surface rounded, as shown, with the smallest internal diameter of the bushing being substantially equal to or slightly greater than the diameter of the shaft 33 so that the latter is journaled in the bushing 114 while being capable of limited tilting movement relative to the bushing. The shaft 38 mounts a collar 116 adjacent the right hand end of the hub N36 for limiting such rocking movement.

From the description it will be seen that film roller 14a is positively driven from the drive shaft 26 through the meshing gears 98 and 100 so that the film 20 is continuously fed into the developing machine at a constant rate dependent on the speed of the drive shaft 26. Moreover, beyond the positively driven roller 14a, the film is frictionally driven through the developing machine by operation of the friction drive roller 48 in tank 10 and the friction drive rollersin the following banks, not shown. The right hand end of shaft 38 is capable of downward movement in response to an increase in tension in the film loops in tank 10 to disengage the upper film rollers from the friction drive roller 48 by virtue of the above described limited tilting movement of the upper shaft 38 in the drive assembly. A substantially constant tension is thereby maintained in the developing machine beyond the drive assembly. The gears 98 and 100, however, remain in meshing engagement during such disengagement ofthe drive rollers and film rollers owing to the gear case 52 which maintains a constant center distance between the gears.

As previously mentioned, and as will be apparent from the foregoing description and drawings, the present drive assembly is in the nature of an attachment which may be readilymounted on a film developing'machine of the type shown in the above mentioned patent or copending application in place of the left hand drive rollers of those developing machines.

It will be apparent therefore that there has been described and illustrated a positive drive assembly for film developing machines of the class described which is fully capable of attaining the objects and advantages preliminarily set forth. While a preferred embodiment of the drive assembly has been disclosed for illustrative purposes, it will be evident that numerous modifications in design and arrangement of parts thereof is possible within the scope of the following claims.

I claim: H I

1. A positive-drive assembly for afilm processing machine of the type including a rotary driving shaft and a film roller shaft parallel to and spaced a given distance from the driving shaft for mounting a plurality of film rollers, said assembly comprising: a gear case including spaced, substantially parallel side walls, a pair of coplanar meshing driving and driven gears between said side walls, said gears having coaxial hubs extending from opposite faces thereof and journaled in said side walls, the hubs of the driving and driven gears having central bores therethrough for receiving said driving and roller shafts respectively, means on the hub of the driving gear for securing the latter to the driving shaft, atleast one end of the hub on the driven gear extending beyond the adjacent hub of the case for mounting a film roller, the bore in the hub of the driven gear being of a diameter to loosely receive the roller shaft, and bearing means in said latter bore for rockably sup'porting said roller shaft in said driven gear.

2. In a film processing machine of the type including a seriesof successive banks at least the first of which includes film supporting feeding means comprising upper and lower film roller shafts rotatably supporting a series of upper and lower coaxial, film rollers about whicha strip of film leading from a supply reel is adapted to be passed in a series of loops, a driving shaft normally parallel to and spaced from the upper one of said roller shafts, and friction roller means adjacent one end of the drive shaft for frictionally driving some of the rollers I on the upper roller shaft, and wherein said upper roller shaft is resiliently supported for rocking movement and tran lation toward and away from the lower roller shaft to disengage the rollers and. friction roller means in response to an increase in the tension in said film loops,

amm

- -the improvements,comprising a positive filmdrive assemof the first bank from the driving shaft of the first bank including a driving member fixed to the driving shaft,

a, driven member coaxial with andrigidly connected to saidone film roller and loosely receiving therethrough the upper rollershaft in the first bank whereby said upper roller shaft is adapted to be rocked relative to the driven member, and common support means mounting said driving and driven members for maintaining a driving relationship therebetween during rocking of said upper roller shaft in the drivenrnember.

3. A positive drive assembly for a film handling machine of. the character described including a tiltable roller shaft, comprising: a support, rotary transmission means including rotary driving and driven members journalled on said support, said driven member having a central axial bore opening to opposite sides ofsai-d support for loosely receiving said roller shaft, bearing means in said bore.

of the driven member for rockably supporting said roller shaft in the driven member, and means for securing a film roller to and concentric with said driven member at one side of said support for positive driving of said film roller by said driven member.

4. A positive drive assembly fora film handling machine of the character described including a tiltable roller shaft, comprising: a support, rotary transmission means including rotary driving and driven members journalled on said support, said driven member having a central axial ,the-diameter of said bore, said bearing means being adapted to receive said roller shaft therethrough for rock- ,ably supporting the latter in said driven member, and

means for securing a film roller to and concentric with said driven member at one side of said support for positive driving of said film roller by said driven member.

5. A positive drive assembly for a film handling machine of the character described including a rotary driving shaft and a tiltable, roller shaft normally substantially paralleling said driving shaft, said driven assembly comprising: a support, rotary transmission means including rotary driving and driven members journalled on said support for rotation about substantially parallelaxes, said driving and driven members having central axial bores opening to opposite sides of said support for receiving, respectively, said drivingand roller shafts, said bore in the driven member being proportioned to loosely receive said roller shaft, bearing means in said bore of the driven member for-rockably supporting said roller shaft in the driven member, and means for securing a film roller to ,and'concentric with said driven member atone side of said support for positive driving of said film roller by said driven member.

'6. A positive drive assembly for a-film handling ma- -.chine of the character described including a tiltable roller for mounting a film roller on and concentric with said ..driven member, and bearing means in said bore of the ;driven member-for rockably supporting said roller shaft in the driven member.

7. A positive drive assemblyfora film handling machine of the character described i'ncludinga tiltable roller shaft, comprising: a support, rotary transmission means including rotary driving and driven members journalled on. said support said driven member having a central axial bore openingtoopposite sides ofsaid support for looselyreceiving baid roller shaft, means for mounting a pair of filmrollers on and concentric with said driven fn iember at oppos te sides of said support, and bearing means in said bore of the driven member for rockably supporting said rller shaft in said driven member.

8. A positive diive assembly for a film handling machine of the character described including a tiltable roller shaft, comprisingna support, rotary transmission means including rotary diving and driven members journalled on saidsupport, sa d driven member having a central hub extending beyond opposite sides of said support for mounting a pair of film rollers, said hub having an axial bore opening through opposite ends thereof for loosely receiving said roller ihaft, and bearing means in said bore for rockably supporting said roller shaft in said driven member. 1

9. The subjectmatter of claim 8 including a film roller mounted on each end of said hub, means fixing one of said film rollers to ;aid hub for rotation with said driven member. e

10. A positive drive assembly for a film handling machine of the character described including driving shaft and a tiltable roller shaft, comprising: a support, a rotary transmission means including rotary driving and driven members journalled on the support for rotation about parallel axes, a film roller. at one side of said support concentric with and fixed to said driven member for rotation with the latter, said driven member and film roller having a central axial bore opening to opposite sides of said support for loosely receiving said roller shaft, and said driving member having an axialbore opening to opposite sides of said support for receiving said driving shaft.

11. In a film professing machine of the character described, the combination of a frame, a rotary driving shaft journalled on said frune, a roller shaft normally parallel to said driving shafz, means rotatably supporting said roller shaft on said frame for rocking of said roller shaft relative to said driving shaft, a plurality of film supporting rollers on said roller shaft, rotary transmission means including a rotary driving member fixed to the driving shaft, a rotary driven member coaxial with and rigidly connected to one of said film rollers, said driven member and one film roller having an axial bore loosely receiving therethrough said roller shaft whereby said roller shaft may rock relative to the driven member, and common support means mounting said driving and driven members with their axes parallel for maintaining a driving relationship therebetween during rocking of said roller shaft in the driven member.

12. The'subject matter of claim 11 wherein said support means comprises spaced side walls journalling said driving and driven members therebetween, said driving member including a coaxial bore opening to opposite sides of the support means and receiving the driving shaft therethrough, means on the driving member releasably securing the latter to the driving shaft, and said driven member includes a central hub having said axial bore formed therethrough, said hub extending beyond at least one side of the support means and having said one film roller rigid thereon.

13. The subject matter of claim 11 including a second film roller journalled on, the side of the support means opposite said one film roller coaxial with the driven member.

14. The subject matter of claim 11 wherein said sup port means comprise spaced side walls having said driving and driven members therebetween, said members including coaxial hubs journalled in the side walls, the hub of the driven member extending beyondopposite sides of the support means, said one film roller being fixed on one end of the latter hub, and a second film roller journalled on the other end of the latter hub.

15. The subject matter of claim 11 including bearing means in said bore rockably supporting said roller shaft in said driven member.

16. The subject matter of claim 11 wherein said support means comprise spaced, parallel side walls, and said driving and driven members comprise meshing, coplanar gears between the side walls and having central coaxial hubs journalled in the opposite side walls, said hub of the driving gear having an axial bore receiving said driving shaft therethrough, means releasably securing the driving gear to the driving shaft, the hub on the driven gear having said first-mentioned axial bore formed therein and extending beyond the opposite side walls, said one film 10 10 roller being fixed on one end of said latter hub, a second film roller journalled on the other end of the latter hub, and bearing means in the bore of the latter hub intermediate said one and second film rollers rockably supporting 5 said roller shaft in said driven gear.

Garbutt July 26, 1927 Steinmann Apr. 19, 1932 

